Speed control.



--C. R. PRATT.

" SPEED CONTROL'.

APPLICATION FILED SEPT. 7, 1910 Patented 1160.311912.

2 SHEETS-SHEET 1.

C. R. PRATT.

SPEED CONTROL.

APPLICATION FILED S11-P11191@ l 1 ,049,000, Patentedl Dec. 31, 1912.

2 :SHEETS-51113112 6i@ F ff by 'UNITED sTATEs PATENT oir-FICE.

omnLEs n. PRATT, or MONTCLAIE, nizwl JERSEY; Assfenon To oTIsl ELEvAToR coMrANY, or JERSEY CITY, NEW JERSEY, A CORPORATION-or NEW JERSEY.

SPEED ooNTRo-L.

Specification of Letters Patent.

Patented Dec. 31,1912.

Application filed September 7', 1910; .Serial No. 580,807.

To all 'whom it `may concern:

Be it known that I, CHARLES R. PRAT'r,"a

[citizen of the United 'States,residing at Montclair, the county of Essex-and. State of New Jersey, have invented a new and Vuseful Improvement in Speed Control, of

which the following isa specification.

,My invention relates 4to controlling mechanism for motors, with particular application to elevator apparatus. A

Objects-of the invention are to provide means for automatically regulating and maintaining uniform speed of amotor regardless of load;l for operating motors in synchronism and to eit'ect'a return to synchronism when the relative speed of the motors varies; for securing any desired speedY of the driving moto-r; for effecting a speedy return ofthe controlling mechanism to stop position; for closing a local or dynamic circuit through the driving motor in stopping;

'for preventing the closure of one reversing switch when the other is closed; for automatically varying the field of an auxiliary or pilot motor when the load on, the driving motor is too great to enable the latter' to attain the. same speed as for a lighter load; and to protect the electrical apparatus and. devices from thelinjurious results incident thereto. i Other objects will appear hereinafter. The mechanism herein ldisclosed involves various mechanical and electrical features embodied in my co-pending application for patent on controlling mechanism for inotors, Serial lNo.I 447,3591 filed August 7,

Figs'. 1 to 3. y

- Referring to they accompanying drawings, .Figure 1 is an elevation' view, partly diagrammatic, showing an'elevator system 'to which my invention is applied; Fig. 2 is a Bctional elevation lof the planet-ary gearing located between the main ,and pilot motors, and the main motor controller adapted t0 be operated by said gearing; Fig. 3 is a View showing the main .motorbrake and the brake opera-ting mechanism Fig. 4 is a' diagrammatic viewV of the electrical circuits and controlling mechanism to be used 'inconnection with theV elevator-'apparatus shown'in In Fig. 1 -is sho'wna Well known ar range-ment of an elevator car'C, counterweight WV, driving motor M, brake B, driving sheave D, and cables l1. The gearing and automatic control devices are preferably located o-n topl of the motor M. Between the motor M and the driving pulley D, the

brake B is located, the latter comprising a brake pulley 12 (Fig. 3) mounted upon the motor shaft,.brake levers 13,r 14'secured'to the magnetcores 15 and adapted'to be applied to the brake pulley 12 by the spring 16 when the magnet cores are not attracted by the magnet 17. The brake applying spring 16 is mounted upon the rod 19 which extends through the brake levers 13 and 14, and the rod is provided at its free end with the adjustable head 20 for the spring, the nut -21 and the buffer 22. A lever 18 is mounted on the brake lever -14 and one arm is connected to the end of the rod l19. To

the other arm of the lever 18 a link 23 is connected. `The operation of this lever 18 will be hereafter setforth.

Referring now to Fig. 2, the casing E contains the gearing forming a connection between the main motor .M and the'pilot motor'P. Journaledl in bearings in the frame E is a shaft 24, to one end of which is 'secured' a sprocket wheel 25 connected by a sprocket chain toa sprocket wheel 10 sel cured to the shaft of the motor M. Key'ed to the sha-ft 24 is a bevel gear wheel 27 oppositea similar gear Wheel28 loosely mounted on the shaft 24. [Between the opposing faces ofthe gears 27 and 28 is a wheel or spider 29l loose on the shaft 24 and carrying bevel pinions 30 journaled on the radial v arms of the spider and each meshing with the gears 27 and 28. The spider 29 also carriesan annular spur gear wheel 31 located loutside of the pinions 30 and meshing with a gear wheel 32'secured to a shaft 33 journaled in'hearingsi. Vto the shaft 33,'m'eshes with a gear Wheel 36 'ournaled on a sleeveB? which also forms'a caring 4for the shaft The ygear Wheel '36 carries a switch-arm 9 providedv .with

electrical lcontacts c, o, "c, d, each in sliding engagement with and bridging tivoarcshaped contacts on'the stationary disk 38 of the .automatic controller K. The sha-ft 39 of the pilotr motor P is provided with a Worm 40 which meshes with a. Worm Wheell-- .41' secured' to 'or formed integral' with the arm normally engages switch contacts d2..

A spring pressed catch i8 formed with a shoulder 4:9 bears against the ysnvitch arm 45, the' shoulder being adaptedto engage beneath andprevent the return of the switch arm after the arm' has been lifted by thev cam 47 v The operation of the mechanism above-den scribed Will bel understood from the lfellowing explanationzAssiiming the parts to be. at .rest and it is desired to start the car, thel switch lever 50 ofthe car switch S is moved either to the right or to the left, depending' on the direct-ionin. which it is desired to move the car. This effects a supply oi current -to the pilot motor P through `circuits vpresently to be described, so that'the said motorv is started and-runs at a speed depending upon they extent of movement of theV sivith lever 5.0. Current is also supplied to thebrake magnet 17 to release the brake levers, and to the main motor M to start and run it at low speed. The pilot. motor P operates through the Wormand Worm wheel torotate the gear Wheel 28 in one direction, and the main motor operates through.` 'the sprocket chain and gears to rotate the gear l Wheel 27' in the opposite direction. vThe rotation of the gear Wheels 27 and 9S rotates the pinions 30 about theiraxis, and as Athe gear Wheel. 28, operated by' the pilot. motor P, vrotates faster 'than the gear Wheel :27, the spider 29, is rotated on the shaft Qf'l. This operates through the gears 31, 32, 35 and 36 to rotate the switch arm 9 and move the .contacts a, b. c, (Z, over the stationary contacts of the controller K. The mo\i'en1ent of the arm 9 causes an increase in the speed of the motor M by eiiecting a weakening of the motor field and a decrease in the resistance in the armature circuit. This increase in speed is in proportion to or 'varies A. pinion 35,'. fixed 4same, Speed. .moved so as to impart a different .speed toA and the motor M continues to accelerate until the gear 27 is running at 'the same.

causes, will cause thearm 9. to move in a direction to bring the motor back to the If the car switch lever is thepilot motor,'the speed of the main mo- 'tor will he correspondingly changed, the diiierential gearing aiways moving the controller arm'9 into position to bring the motors into synchronism.

In YF ig. el,v the electrical circuits and controlling mechanism forming a. part of my invention are shown as applied to an eleva# "t'or. system. This mechanism comprises a Zmanual car switch Si, an automatic controller K, reversing' switches R, R, for the armature circuits of the main motor, starting resistance for the mainv motor, relay magnets N, 0, J, to control the starting resistances, brake magnet coil 51 and shunt iield Winding 53. for the main motor, brake magnetcoil 54 and shunt tield Winding 52 'for the pilot motor, magnets Y and Z to control the circuits. of the pilot motor reversing switches, and various other controlling n'iagn'its, the operation of which Will be SubseQUentlyset forth. The manual car switch S comprises the lever 50 carrying insulated contacts 54, 55, each adapted to bridge stationary contacts when the lever is moved to the right or left from the central position.- The arm 9 of the controllerl K carries iour insulated contacts, a, c, and d, eachv adapted to bridge various sets of contacts as the arm 9 is moved.

Current is supplied from the positive and negative mains, designated by -land respecti'vely. In Fig. 4 the controlling .apparatiis is shown With the various partsin their normal position of rest. T he circuit for the magnet N extends from the -lmain through the wi-re 101, Contact bar 88 of magnet Q,

controller contact c, Wire 102, magnet N, and

-. Wire 'Zito the main. The magnet N being energized short-circuits the armature resistance,.comprising the sect1ons67,'67, 68 and 69. A local-or dynamic circuit across the motor armature may be traced from the brushed', through contact barsy 58, 62, 57, of the reversing switches R and l', thence through the conductor 103, lower contacts of magnet N, conduct-or 10i, contact bars 61, 66, (33, and to the brush 56. The field coil52 of the pilot motor receives current at all times through a circuit Which-may be traced from the -imain, through 'conductor 70, contacts 72, 54, 71, of switch S, through field Winding 52 and Wire 74 to the main. Ii now, it is desired to start the car in an upmagnet Z by way vof the wire 70, contacts `106, 55, 105', magnet Z and wire/74. .The magnet Z being venergized lifts its -contact bars 75, 76, 77`and establishes a circuit from the lpositive main through conductors 70, 97, lo contact bar 75, armature of pilot motor P,

- coils V and T, conductor 79,V contactbar 76 an l -wire 74. The magnet T lifts its contact bar 80 to4 close Aa circuit'through the' main-brake coil 51' as follows: from the -lmain through the' wires 70, 107, contact bar" 80, brake coil 51, cont-acts 42, switcharm 45,' and from thence to the wire 74.V The magnet V does not lift its armature, buti's- 2-used later as' a holding maanet whenthe magnet WV is operated. The operationif the magnet Z, also establishes a circuit through the reversing ,switch winding R', by way of conductors.70, and 97, contact bar 77, conductor 81, and contact bar 82 of magnet WV, magnet winding 'X2 conductor 83, auxiliary contacts 84, lreversing switch magnet winding lt', conductor 85, magnet winding Q,'and to the-- main. 4The magnet Q'being energized, lifts the contact bar 88 and breaks the circuit through the magnet N, so that the latter opensthe short circuitacross the armature resistance. The op eration of themagnet X establishes a circuit for the magnet O as follows: from the main through wires70, 108, 109, 'contact bar 89, Wire 110, magnet 0 and. thence tothe main. The magnet O being energized, its upper contact-s shqrt'circuitthe section 68 of the armature resistances, leaving only thesections 67, 67, .to act as a starting res'istance.` The armature circuit established by the reversing magnet- R', is from the main through conductor 101, vContact bar 64,` to brush 56, through the armature to brush.

55', contact bar 65, conductor 112, through the short circuitacross the resistance 68, through resistances 67', 67, .conductor 113, contact bar 66 and thence to the main.

brakes, and both the motors receive current through their armatures and field windings and will start to lrun atvsubstan'tially" the same-time. `The speed to which the pilot 4motor accelerates will depend on the-^dis tance the switch S is moved to the' right. Asthe switch'is moved away from the central position, the resistance .73 is graduall introduced into the circuit of the field wind ing 52, thereby weakening the field and ac. -celerat-ing the pilot motor. The main motor starts in a direction to lift the cnr, with the starting resistances 67, 67', in the ar1nature circuit, 4and a. strong magnetic field.

brake magnet coil 5 4, conductor 7 8, magnet" l As a`result of the circuits above'traced the brakev magnets are energized to lift the,

The speed 'of the main motor being-rela tively slower than that of the pilot motor,

the differential gearing'tFig. 2) willoper- -ate as already described tomo've the arm 9 of the controller K ina counter-clockwise 70 direction.v 'This gradually introduces the field resistance in circuit with the main field winding 53 and causes the motor .hf to accelerate. The difference in speed of the main a'nd pilot'motors will cause thediferential gear to rotate the arm 9,' until the'v speed of the main motor vhas been so changed as to correspond with that of the pilot m0- tor, and at this time the two gear wheels 27I andv 28, (Fig. 2)' will rotate insynchronism. 80 WVhen the arm 9 has rotated far enough for the contact b to engage the cont-act segment 91, a-circuit is established through the magnetsL and U las follows: from the'fmain, through conductorlOl, magnet L,"contact '85 ring 92, contact contactsegment 91, wire 114, magnet U', and to the main. The magnet L being energized liftsits Contact bar 93'in th'e circuit commonfto the magnets N,.O, J, which circuit wasopened by the 90 operation of the magnet Q. This has no immediate ett'ect,'the magnets N andJ remaining dead forthe present, but themag- Anet O is energized independently ofits circuit throughthe controller K. The magnet 95 lU', by raising Yits contact bars, will' estab- Y lish circuit connections from the positive main to the conductor 8 3, to brake magnet winding 51, to magnet winding W, and tov conductor 94. The niagnetwinding'/V' when 100 energized, lifts its cores Awithin the magnetic field of the magnetV, which being euergized retains the core in .the lifted position, That is, the switch of the magnet W- isj held open in'depe'ndentl of the' v magnet 105 U', which. if the controler arm 9 vwere moved off the contact 91', would immediately drop its core and open the circuit to the magnet YV. Raising the contact bar 82 breaks the circuit through' the magnet wind- 110` ing .X and allows the conta-ct bar 89 to drop. This opens the circuit of the magnet O, and4` inserts the resistance68' in the armature cir cuit.. lf the controller ar1n'9 continues to rotate to `the right, the Contact @engages the Pcontactsegments 115 and 116', thus 'energiz-v ,ing the magnets O'and N and thereby cuttingout the Vstarting resistance. v

The operation ofthe magnet lV, as above Y noted, opens the original circuit through 1z0 the reversing switch R established through the switch of magnet Z. This keeps thereversing switch vcoil R vfrom the control of the magnet Z-until the'car switch hand lever 50 is returned to stop position. This places, 125: the reversing switclrR and brake 51 under l control of the Contact arm 9 and out of the control of the car switch, so that the contact arm will always be moved back toward central position to slow downthc motor before series the supply circuit is opened, thereby prevent-ing a sudden cutting oil' of the current and application of the brake when the pilot switch S is* quickly or momentarily returned to stop position.

Energi'zation of the magnet L, is preferably affected only when .it` is desired to drive the main motor M with its maximum load. At this time the magnet N will be energized to cut outv all the resistance inwith the main motor armature. Should the main motor be unable to raise the load to a speed in synchronism to the pilot motor, .the contact arm 9 will be advanced until the brush A makes connection with the Contact segments 96 and the sectional re'- /sistance contacts 95, which closea circuit around resistance 73 of the pilot motor -field winding52 to slow down the pilot is out ofi', but if the speed of the motorsl has beenso great that the brush b made contact with the contact strip 91 the magnet U will be energized. and a circuit will be closed by way of conductor 94, lower vcontact bar 77 of the magnet Zand through the magnet winding Y. This will energize the pilot 4, motor P to cause `rotation thereof in a direction opposite to that in .which it has been running. The result of this is to return the contact larm to the central or stop` position rapidly, and to bring the main motor quickly to rest. As the contact slides off the Contact strip 91, the circuit through the magnet winding U is broken, .thereby breaking the circuits through the magnet windings R', Y Vand Q, causing their contactbars to return to their normal positions. rThis will sever the connection of the main motor` armature to the supply mains, will stop the kpilot motor P, and will. complete ai local or armature circuit, with the resistances 67, 68, 69 :in series. The Q, magnet bar S8 now being down the short circuiting magnets J, O, N, are energized in the order named to short circuit their respective resistances as the contacts on the controller K are reached by the contact c. This gradually decreases the resistance in the dynamic circuit and slows down the main `motor, without manual attention thereto. l

During the normal operation the controller arm 9l is never vrotated beyond the Contact strip 91, for the main motor wil-l synchronize with the highest iwrmal speed of the pilot motor before the arm 9 has been rotated beyond the said contact. lf howiever, while the motor y floladed, the current should suddenly be out loff, as forA example by t-he blowing of a fuse, the load would cause the main motor to reverse land thus drive the arm 9 rapidly upward toward the contacts 98, 99, 100. This would have s ubstantially the same eiiect as moving said arm toward central position; for these con- 'tacts are connected with thecontacts ywhich control the short circuiting magnets J, O, N. If, however, the trouble were l1n sofie pen tion of thedynamic circuit, so that the said circuit remained open, the arm 9 might be carried around until the cam 47 Y(Figs. Q and 3) engaged the roller 46 on. the switch arm 45 and lifts the said arm. The arm 45 operates through the arm.48, link 23, and lever 18, positively to apply the brake. The operation of the arm 45 also opens .the circuits of the brake winding 5l at the contacts 42. The combined operation of the tvvo brake applying devices is therefore obtained, ,which effects a powerful action of the main brake.

'To move the car downward the switch lever 50 is moved to the left. The subsequent action is similar to the action upon the-upward movement, the magnets Y, R, X and U, being energized instead of the up magnets corresponding thereto, the other magnets being common to both up and down operations. y

Further description is not deemed necessary, the operation of the various devices being sufliciently setv forth in the foregoing description.

lVhile I have thus described the preferred embodiment .of my invention, I desire not to be limited to'` the Yprecise construction, combination, and arrangement shown, as it is evident that those skilled in the art'may make various changes without .departing from. the spirit andV scope of the invention.

lVhat l claim and desire to secure by Letters Patent of the United States is l. The combination with a main motor and a pilot motor, of means to varyr and con 'trol the speed of the pilot motor, differential gearing between the motors, reversing switches for the main motor, -me'ans for clo'sing one of the reversing switches when the pilot motor is started, means to maintain the main motor at a speed in synchronism with the pilot motor and means to preventv the closure of the `other reversing switch while the first one is closed.

Q. The combination with a main motor and a pilot motor, of differential gearing 'between the motors, means for controlling the pilot motor, a cont-roller for the main -niotor operated by the differential gearing,

and Ameans in connection with the controller for rec'lucing' the speed of the pilot motor when 4the load upon the main motor is too great.

,3. `The combination with al main motor A andjaV pilot motor,

I between the motors,'a control leroperated by they gearing, means for controlling the direcs'tion '1n which the motors. operate, anda magnet' automatically closed when the -main v motoruattains a predetermined speed and operative to maintain the main motor in normal operation until the said gearingr ef- 10 fects a-change in speed of the main motor. 4. The combination with a main' motor `'and a pilot motor, of diierential gearing bey "tween the motors, a controller for the main motor operated by -the gearing, 4reversing switches for the pilotmotor, means for controlling the main motor when one of the said reversing switches is closed,fand means wherebg the Aother reversing switch is closed when t e closed switch is opened to effect a `20 rapid operationof the gearing tostop the main motor.VIA l 5..The combination with' a main motor nd a pilot motor, of-means for controllingthe direction of rotation of the motors,

an automatic controller for the main motor,

a magnet switch automatically closed-whenthe Amain motor attains a predetermined As eed, and means for closing a lcircuit t' ough the pilot-motor armature in a re-` 9,0 verse direction when itis desired to stop the main motor.`

.'6'. 'The combination with a main motori and a pilot motor, of electro-responsive re- 'versing switches for the pilot motor, reversing switches furthe main .motor actuated by theoperation -of the pilot 'motor switches, a controller automatically operated by a change in relative speed of the moi tors, a vmagnet switch closed when the main motor attains 'a predetermined speed, and

other electro-responsive reversing switch lis open andthe said magnetswitch is` closed.

pilot motor in the stopping of the main inotor isreversed in direction to effect a more rapid Vreturn of thev controllerA to stop position than by the. operation of the main motor alone@ --fxq 8.- The combination with a :main motor tional resistance controlled by said switches and in series with the main motor armature,

reversing switches for the main motor and for the pilot motor, an electro-responsive C. device operative to energize one of said magnet switches whenV a pilot'motor reversing switch is closed, a magnet energize the last named device, and means `whereby the sectional resistance may I u ort-'cumited independently of the said of differenti-al gearing means'for establishing a circuit through one'V electro-responsive reversing switch when the 7. rlhe'. combination with a. main motor and a pilot 'motor, .of diilerential gear# l ing between the motors, a controller oper# 1, ated by the gearing', and means whereby the and a pilot motor, of magnet switches, secoperative to de electro-responsive device ,to accelerate the main motor. 7 4 9v.y .The combination'- with a 'main motor and avpilot motor, of diferential gearing between the motors, a controller operated by :70 the gearing, sectional resistance and shortf circuiting magnets therefor for the'inain fniotor, reversing switches for the mainlnotor and the pilot motor, a 'double' wound .magnet 4operati-vel to .energize one ofl thel 75 short-circuiting magnet-s when a' pilot motor'- reversing switch .1s closed, means for pre-` venting the sliort-circuiting 'of more of the sectional resistanceu'nt-il the mainmotor attains a predetermined speed, and means '80 thereafter operative' to render the double `wound magnetof no effect and to placethe short-circuitin'g magnets-.under the control'4 of the controller. f

10. The combination withai'nain lmotor 8 5;

and a pilot motor, of'p'lanetary gearing vbetween'the motors, a controller governed by the gearing, sectional resistance forthe main motor with short-circuiting magnets therefor, means for utilizin'gone sect-ion of 90 tween the motors, a controller4 operated by 100 the gearing, sectional resistance for the main motor, short-circuiting magnets for the resistance, means to establish a circuit for one of said magnets andv cause its oper-- ation when the main motor is started, means to preventthe operation of another of said v,

magnets until a predetermined is'attained by the motor, and mean tofjrender all of said magnetsoperative'i i bringing the motor 'to a stop. 1 12. The combination with af-.main motor and apilotV motor, of epicyclicgearing between the motors, a controller operated by the. gearing, sectional resistance for the main motor, short-circuiting magnets for 1.15 -the resistance, means -toestablish 'a circuit for one of saidmagn'etsf'fwhen the mainmo- I tor I is started, main; motor 1 f-regersing switches," and a, magnet .energl v either reversing switch is energizediand ef- @when feetive thereupon to open the 'common-'circuit of the short-circuiting magnets. A

13. The combination with a'main motor?4 and a pilot motor,f of epicyclic gearing be tween the.A motors, a controller operated bythe gearing, sectional 'resistance for the main motor, short-circuiting magnets for the resistance, means to-operate o ne of said magnets when the main motor is started, imm motor reversing switches, a magnet energized When either reversing switch is In testimony whereof, I have signed my energized and effective 4thereupon t0 open name to this specication in the presence 0f the common clrcult of the short-cnculting two subscrlbmg wltnesses.

magnets, and a. magnet energized when the CHARLES R. PRATT. motor attains' e predetermined speed and VVtnessesz operative t0 close the commen circuit to the T. WV. BISCHOFF, short-eircutng magnets. l H. T. JOHNSN.

Copies of this pafent may-be obtained for ve cents-each, by 4edressing the f Commissioner of Patents,

' Washington, D. G. 

